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authorStephen Hemminger <shemminger@osdl.org>2005-11-03 16:33:23 -0800
committerArnaldo Carvalho de Melo <acme@mandriva.com>2005-11-05 21:23:15 -0200
commit6df716340da3a6fdd33d73d7ed4c6f7590ca1c42 (patch)
tree1b3ba3d1a0a08b9b4eaa624a66414b87a70b6fe9 /net/ipv4/inet_connection_sock.c
parent6151b31c9616d71f714fc7ef8e2306f67f3b94c3 (diff)
[TCP/DCCP]: Randomize port selection
This patch randomizes the port selected on bind() for connections to help with possible security attacks. It should also be faster in most cases because there is no need for a global lock. Signed-off-by: Stephen Hemminger <shemminger@osdl.org> Signed-off-by: Arnaldo Carvalho de Melo <acme@mandriva.com>
Diffstat (limited to 'net/ipv4/inet_connection_sock.c')
-rw-r--r--net/ipv4/inet_connection_sock.c14
1 files changed, 3 insertions, 11 deletions
diff --git a/net/ipv4/inet_connection_sock.c b/net/ipv4/inet_connection_sock.c
index 94468a76c5b..3fe021f1a56 100644
--- a/net/ipv4/inet_connection_sock.c
+++ b/net/ipv4/inet_connection_sock.c
@@ -78,17 +78,9 @@ int inet_csk_get_port(struct inet_hashinfo *hashinfo,
int low = sysctl_local_port_range[0];
int high = sysctl_local_port_range[1];
int remaining = (high - low) + 1;
- int rover;
+ int rover = net_random() % (high - low) + low;
- spin_lock(&hashinfo->portalloc_lock);
- if (hashinfo->port_rover < low)
- rover = low;
- else
- rover = hashinfo->port_rover;
do {
- rover++;
- if (rover > high)
- rover = low;
head = &hashinfo->bhash[inet_bhashfn(rover, hashinfo->bhash_size)];
spin_lock(&head->lock);
inet_bind_bucket_for_each(tb, node, &head->chain)
@@ -97,9 +89,9 @@ int inet_csk_get_port(struct inet_hashinfo *hashinfo,
break;
next:
spin_unlock(&head->lock);
+ if (++rover > high)
+ rover = low;
} while (--remaining > 0);
- hashinfo->port_rover = rover;
- spin_unlock(&hashinfo->portalloc_lock);
/* Exhausted local port range during search? It is not
* possible for us to be holding one of the bind hash